package unit3.test;
import java.util.Scanner;

public class NJieCheng {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int num = scanner.nextInt();

        int result = 1;
        for (int i = 1; i <= num; i++) {
            result = result * i;
        }
        System.out.println(result);
    }
}
